uboot/drivers/mtd/ubi/ubi.h
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   1/*
   2 * Copyright (c) International Business Machines Corp., 2006
   3 * Copyright (c) Nokia Corporation, 2006, 2007
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  13 * the GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18 *
  19 * Author: Artem Bityutskiy (Битюцкий Артём)
  20 */
  21
  22#ifndef __UBI_UBI_H__
  23#define __UBI_UBI_H__
  24
  25#ifdef UBI_LINUX
  26#include <linux/init.h>
  27#include <linux/types.h>
  28#include <linux/list.h>
  29#include <linux/rbtree.h>
  30#include <linux/sched.h>
  31#include <linux/wait.h>
  32#include <linux/mutex.h>
  33#include <linux/rwsem.h>
  34#include <linux/spinlock.h>
  35#include <linux/fs.h>
  36#include <linux/cdev.h>
  37#include <linux/device.h>
  38#include <linux/string.h>
  39#include <linux/vmalloc.h>
  40#include <linux/mtd/mtd.h>
  41#include <linux/mtd/ubi.h>
  42#endif
  43
  44#include <linux/types.h>
  45#include <linux/list.h>
  46#include <linux/rbtree.h>
  47#include <linux/string.h>
  48#include <linux/mtd/mtd.h>
  49#include <linux/mtd/ubi.h>
  50
  51#include "ubi-media.h"
  52#include "scan.h"
  53#include "debug.h"
  54
  55/* Maximum number of supported UBI devices */
  56#define UBI_MAX_DEVICES 32
  57
  58/* UBI name used for character devices, sysfs, etc */
  59#define UBI_NAME_STR "ubi"
  60
  61/* Normal UBI messages */
  62#define ubi_msg(fmt, ...) printk(KERN_NOTICE "UBI: " fmt "\n", ##__VA_ARGS__)
  63/* UBI warning messages */
  64#define ubi_warn(fmt, ...) printk(KERN_WARNING "UBI warning: %s: " fmt "\n", \
  65                                  __func__, ##__VA_ARGS__)
  66/* UBI error messages */
  67#define ubi_err(fmt, ...) printk(KERN_ERR "UBI error: %s: " fmt "\n", \
  68                                 __func__, ##__VA_ARGS__)
  69
  70/* Lowest number PEBs reserved for bad PEB handling */
  71#define MIN_RESEVED_PEBS 2
  72
  73/* Background thread name pattern */
  74#define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"
  75
  76/* This marker in the EBA table means that the LEB is um-mapped */
  77#define UBI_LEB_UNMAPPED -1
  78
  79/*
  80 * In case of errors, UBI tries to repeat the operation several times before
  81 * returning error. The below constant defines how many times UBI re-tries.
  82 */
  83#define UBI_IO_RETRIES 3
  84
  85/*
  86 * Error codes returned by the I/O unit.
  87 *
  88 * UBI_IO_PEB_EMPTY: the physical eraseblock is empty, i.e. it contains only
  89 * 0xFF bytes
  90 * UBI_IO_PEB_FREE: the physical eraseblock is free, i.e. it contains only a
  91 * valid erase counter header, and the rest are %0xFF bytes
  92 * UBI_IO_BAD_EC_HDR: the erase counter header is corrupted (bad magic or CRC)
  93 * UBI_IO_BAD_VID_HDR: the volume identifier header is corrupted (bad magic or
  94 * CRC)
  95 * UBI_IO_BITFLIPS: bit-flips were detected and corrected
  96 */
  97enum {
  98        UBI_IO_PEB_EMPTY = 1,
  99        UBI_IO_PEB_FREE,
 100        UBI_IO_BAD_EC_HDR,
 101        UBI_IO_BAD_VID_HDR,
 102        UBI_IO_BITFLIPS
 103};
 104
 105/**
 106 * struct ubi_wl_entry - wear-leveling entry.
 107 * @rb: link in the corresponding RB-tree
 108 * @ec: erase counter
 109 * @pnum: physical eraseblock number
 110 *
 111 * This data structure is used in the WL unit. Each physical eraseblock has a
 112 * corresponding &struct wl_entry object which may be kept in different
 113 * RB-trees. See WL unit for details.
 114 */
 115struct ubi_wl_entry {
 116        struct rb_node rb;
 117        int ec;
 118        int pnum;
 119};
 120
 121/**
 122 * struct ubi_ltree_entry - an entry in the lock tree.
 123 * @rb: links RB-tree nodes
 124 * @vol_id: volume ID of the locked logical eraseblock
 125 * @lnum: locked logical eraseblock number
 126 * @users: how many tasks are using this logical eraseblock or wait for it
 127 * @mutex: read/write mutex to implement read/write access serialization to
 128 *         the (@vol_id, @lnum) logical eraseblock
 129 *
 130 * This data structure is used in the EBA unit to implement per-LEB locking.
 131 * When a logical eraseblock is being locked - corresponding
 132 * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
 133 * See EBA unit for details.
 134 */
 135struct ubi_ltree_entry {
 136        struct rb_node rb;
 137        int vol_id;
 138        int lnum;
 139        int users;
 140        struct rw_semaphore mutex;
 141};
 142
 143struct ubi_volume_desc;
 144
 145/**
 146 * struct ubi_volume - UBI volume description data structure.
 147 * @dev: device object to make use of the the Linux device model
 148 * @cdev: character device object to create character device
 149 * @ubi: reference to the UBI device description object
 150 * @vol_id: volume ID
 151 * @ref_count: volume reference count
 152 * @readers: number of users holding this volume in read-only mode
 153 * @writers: number of users holding this volume in read-write mode
 154 * @exclusive: whether somebody holds this volume in exclusive mode
 155 *
 156 * @reserved_pebs: how many physical eraseblocks are reserved for this volume
 157 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 158 * @usable_leb_size: logical eraseblock size without padding
 159 * @used_ebs: how many logical eraseblocks in this volume contain data
 160 * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
 161 * @used_bytes: how many bytes of data this volume contains
 162 * @alignment: volume alignment
 163 * @data_pad: how many bytes are not used at the end of physical eraseblocks to
 164 *            satisfy the requested alignment
 165 * @name_len: volume name length
 166 * @name: volume name
 167 *
 168 * @upd_ebs: how many eraseblocks are expected to be updated
 169 * @ch_lnum: LEB number which is being changing by the atomic LEB change
 170 *           operation
 171 * @ch_dtype: data persistency type which is being changing by the atomic LEB
 172 *            change operation
 173 * @upd_bytes: how many bytes are expected to be received for volume update or
 174 *             atomic LEB change
 175 * @upd_received: how many bytes were already received for volume update or
 176 *                atomic LEB change
 177 * @upd_buf: update buffer which is used to collect update data or data for
 178 *           atomic LEB change
 179 *
 180 * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
 181 * @checked: %1 if this static volume was checked
 182 * @corrupted: %1 if the volume is corrupted (static volumes only)
 183 * @upd_marker: %1 if the update marker is set for this volume
 184 * @updating: %1 if the volume is being updated
 185 * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
 186 *
 187 * @gluebi_desc: gluebi UBI volume descriptor
 188 * @gluebi_refcount: reference count of the gluebi MTD device
 189 * @gluebi_mtd: MTD device description object of the gluebi MTD device
 190 *
 191 * The @corrupted field indicates that the volume's contents is corrupted.
 192 * Since UBI protects only static volumes, this field is not relevant to
 193 * dynamic volumes - it is user's responsibility to assure their data
 194 * integrity.
 195 *
 196 * The @upd_marker flag indicates that this volume is either being updated at
 197 * the moment or is damaged because of an unclean reboot.
 198 */
 199struct ubi_volume {
 200        struct device dev;
 201        struct cdev cdev;
 202        struct ubi_device *ubi;
 203        int vol_id;
 204        int ref_count;
 205        int readers;
 206        int writers;
 207        int exclusive;
 208
 209        int reserved_pebs;
 210        int vol_type;
 211        int usable_leb_size;
 212        int used_ebs;
 213        int last_eb_bytes;
 214        long long used_bytes;
 215        int alignment;
 216        int data_pad;
 217        int name_len;
 218        char name[UBI_VOL_NAME_MAX+1];
 219
 220        int upd_ebs;
 221        int ch_lnum;
 222        int ch_dtype;
 223        long long upd_bytes;
 224        long long upd_received;
 225        void *upd_buf;
 226
 227        int *eba_tbl;
 228        unsigned int checked:1;
 229        unsigned int corrupted:1;
 230        unsigned int upd_marker:1;
 231        unsigned int updating:1;
 232        unsigned int changing_leb:1;
 233
 234#ifdef CONFIG_MTD_UBI_GLUEBI
 235        /*
 236         * Gluebi-related stuff may be compiled out.
 237         * TODO: this should not be built into UBI but should be a separate
 238         * ubimtd driver which works on top of UBI and emulates MTD devices.
 239         */
 240        struct ubi_volume_desc *gluebi_desc;
 241        int gluebi_refcount;
 242        struct mtd_info gluebi_mtd;
 243#endif
 244};
 245
 246/**
 247 * struct ubi_volume_desc - descriptor of the UBI volume returned when it is
 248 * opened.
 249 * @vol: reference to the corresponding volume description object
 250 * @mode: open mode (%UBI_READONLY, %UBI_READWRITE, or %UBI_EXCLUSIVE)
 251 */
 252struct ubi_volume_desc {
 253        struct ubi_volume *vol;
 254        int mode;
 255};
 256
 257struct ubi_wl_entry;
 258
 259/**
 260 * struct ubi_device - UBI device description structure
 261 * @dev: UBI device object to use the the Linux device model
 262 * @cdev: character device object to create character device
 263 * @ubi_num: UBI device number
 264 * @ubi_name: UBI device name
 265 * @vol_count: number of volumes in this UBI device
 266 * @volumes: volumes of this UBI device
 267 * @volumes_lock: protects @volumes, @rsvd_pebs, @avail_pebs, beb_rsvd_pebs,
 268 *                @beb_rsvd_level, @bad_peb_count, @good_peb_count, @vol_count,
 269 *                @vol->readers, @vol->writers, @vol->exclusive,
 270 *                @vol->ref_count, @vol->mapping and @vol->eba_tbl.
 271 * @ref_count: count of references on the UBI device
 272 *
 273 * @rsvd_pebs: count of reserved physical eraseblocks
 274 * @avail_pebs: count of available physical eraseblocks
 275 * @beb_rsvd_pebs: how many physical eraseblocks are reserved for bad PEB
 276 *                 handling
 277 * @beb_rsvd_level: normal level of PEBs reserved for bad PEB handling
 278 *
 279 * @autoresize_vol_id: ID of the volume which has to be auto-resized at the end
 280 *                     of UBI ititializetion
 281 * @vtbl_slots: how many slots are available in the volume table
 282 * @vtbl_size: size of the volume table in bytes
 283 * @vtbl: in-RAM volume table copy
 284 * @volumes_mutex: protects on-flash volume table and serializes volume
 285 *                 changes, like creation, deletion, update, resize
 286 *
 287 * @max_ec: current highest erase counter value
 288 * @mean_ec: current mean erase counter value
 289 *
 290 * @global_sqnum: global sequence number
 291 * @ltree_lock: protects the lock tree and @global_sqnum
 292 * @ltree: the lock tree
 293 * @alc_mutex: serializes "atomic LEB change" operations
 294 *
 295 * @used: RB-tree of used physical eraseblocks
 296 * @free: RB-tree of free physical eraseblocks
 297 * @scrub: RB-tree of physical eraseblocks which need scrubbing
 298 * @prot: protection trees
 299 * @prot.pnum: protection tree indexed by physical eraseblock numbers
 300 * @prot.aec: protection tree indexed by absolute erase counter value
 301 * @wl_lock: protects the @used, @free, @prot, @lookuptbl, @abs_ec, @move_from,
 302 *           @move_to, @move_to_put @erase_pending, @wl_scheduled, and @works
 303 *           fields
 304 * @move_mutex: serializes eraseblock moves
 305 * @wl_scheduled: non-zero if the wear-leveling was scheduled
 306 * @lookuptbl: a table to quickly find a &struct ubi_wl_entry object for any
 307 *             physical eraseblock
 308 * @abs_ec: absolute erase counter
 309 * @move_from: physical eraseblock from where the data is being moved
 310 * @move_to: physical eraseblock where the data is being moved to
 311 * @move_to_put: if the "to" PEB was put
 312 * @works: list of pending works
 313 * @works_count: count of pending works
 314 * @bgt_thread: background thread description object
 315 * @thread_enabled: if the background thread is enabled
 316 * @bgt_name: background thread name
 317 *
 318 * @flash_size: underlying MTD device size (in bytes)
 319 * @peb_count: count of physical eraseblocks on the MTD device
 320 * @peb_size: physical eraseblock size
 321 * @bad_peb_count: count of bad physical eraseblocks
 322 * @good_peb_count: count of good physical eraseblocks
 323 * @min_io_size: minimal input/output unit size of the underlying MTD device
 324 * @hdrs_min_io_size: minimal I/O unit size used for VID and EC headers
 325 * @ro_mode: if the UBI device is in read-only mode
 326 * @leb_size: logical eraseblock size
 327 * @leb_start: starting offset of logical eraseblocks within physical
 328 * eraseblocks
 329 * @ec_hdr_alsize: size of the EC header aligned to @hdrs_min_io_size
 330 * @vid_hdr_alsize: size of the VID header aligned to @hdrs_min_io_size
 331 * @vid_hdr_offset: starting offset of the volume identifier header (might be
 332 * unaligned)
 333 * @vid_hdr_aloffset: starting offset of the VID header aligned to
 334 * @hdrs_min_io_size
 335 * @vid_hdr_shift: contains @vid_hdr_offset - @vid_hdr_aloffset
 336 * @bad_allowed: whether the MTD device admits of bad physical eraseblocks or
 337 *               not
 338 * @mtd: MTD device descriptor
 339 *
 340 * @peb_buf1: a buffer of PEB size used for different purposes
 341 * @peb_buf2: another buffer of PEB size used for different purposes
 342 * @buf_mutex: proptects @peb_buf1 and @peb_buf2
 343 * @dbg_peb_buf: buffer of PEB size used for debugging
 344 * @dbg_buf_mutex: proptects @dbg_peb_buf
 345 */
 346struct ubi_device {
 347        struct cdev cdev;
 348        struct device dev;
 349        int ubi_num;
 350        char ubi_name[sizeof(UBI_NAME_STR)+5];
 351        int vol_count;
 352        struct ubi_volume *volumes[UBI_MAX_VOLUMES+UBI_INT_VOL_COUNT];
 353        spinlock_t volumes_lock;
 354        int ref_count;
 355
 356        int rsvd_pebs;
 357        int avail_pebs;
 358        int beb_rsvd_pebs;
 359        int beb_rsvd_level;
 360
 361        int autoresize_vol_id;
 362        int vtbl_slots;
 363        int vtbl_size;
 364        struct ubi_vtbl_record *vtbl;
 365        struct mutex volumes_mutex;
 366
 367        int max_ec;
 368        /* TODO: mean_ec is not updated run-time, fix */
 369        int mean_ec;
 370
 371        /* EBA unit's stuff */
 372        unsigned long long global_sqnum;
 373        spinlock_t ltree_lock;
 374        struct rb_root ltree;
 375        struct mutex alc_mutex;
 376
 377        /* Wear-leveling unit's stuff */
 378        struct rb_root used;
 379        struct rb_root free;
 380        struct rb_root scrub;
 381        struct {
 382                struct rb_root pnum;
 383                struct rb_root aec;
 384        } prot;
 385        spinlock_t wl_lock;
 386        struct mutex move_mutex;
 387        struct rw_semaphore work_sem;
 388        int wl_scheduled;
 389        struct ubi_wl_entry **lookuptbl;
 390        unsigned long long abs_ec;
 391        struct ubi_wl_entry *move_from;
 392        struct ubi_wl_entry *move_to;
 393        int move_to_put;
 394        struct list_head works;
 395        int works_count;
 396        struct task_struct *bgt_thread;
 397        int thread_enabled;
 398        char bgt_name[sizeof(UBI_BGT_NAME_PATTERN)+2];
 399
 400        /* I/O unit's stuff */
 401        long long flash_size;
 402        int peb_count;
 403        int peb_size;
 404        int bad_peb_count;
 405        int good_peb_count;
 406        int min_io_size;
 407        int hdrs_min_io_size;
 408        int ro_mode;
 409        int leb_size;
 410        int leb_start;
 411        int ec_hdr_alsize;
 412        int vid_hdr_alsize;
 413        int vid_hdr_offset;
 414        int vid_hdr_aloffset;
 415        int vid_hdr_shift;
 416        int bad_allowed;
 417        struct mtd_info *mtd;
 418
 419        void *peb_buf1;
 420        void *peb_buf2;
 421        struct mutex buf_mutex;
 422        struct mutex ckvol_mutex;
 423#ifdef CONFIG_MTD_UBI_DEBUG
 424        void *dbg_peb_buf;
 425        struct mutex dbg_buf_mutex;
 426#endif
 427};
 428
 429extern struct kmem_cache *ubi_wl_entry_slab;
 430extern struct file_operations ubi_ctrl_cdev_operations;
 431extern struct file_operations ubi_cdev_operations;
 432extern struct file_operations ubi_vol_cdev_operations;
 433extern struct class *ubi_class;
 434extern struct mutex ubi_devices_mutex;
 435
 436/* vtbl.c */
 437int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
 438                           struct ubi_vtbl_record *vtbl_rec);
 439int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si);
 440
 441/* vmt.c */
 442int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req);
 443int ubi_remove_volume(struct ubi_volume_desc *desc);
 444int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs);
 445int ubi_add_volume(struct ubi_device *ubi, struct ubi_volume *vol);
 446void ubi_free_volume(struct ubi_device *ubi, struct ubi_volume *vol);
 447
 448/* upd.c */
 449int ubi_start_update(struct ubi_device *ubi, struct ubi_volume *vol,
 450                     long long bytes);
 451int ubi_more_update_data(struct ubi_device *ubi, struct ubi_volume *vol,
 452                         const void __user *buf, int count);
 453int ubi_start_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
 454                         const struct ubi_leb_change_req *req);
 455int ubi_more_leb_change_data(struct ubi_device *ubi, struct ubi_volume *vol,
 456                             const void __user *buf, int count);
 457
 458/* misc.c */
 459int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf, int length);
 460int ubi_check_volume(struct ubi_device *ubi, int vol_id);
 461void ubi_calculate_reserved(struct ubi_device *ubi);
 462
 463/* gluebi.c */
 464#ifdef CONFIG_MTD_UBI_GLUEBI
 465int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol);
 466int ubi_destroy_gluebi(struct ubi_volume *vol);
 467void ubi_gluebi_updated(struct ubi_volume *vol);
 468#else
 469#define ubi_create_gluebi(ubi, vol) 0
 470
 471static inline int ubi_destroy_gluebi(struct ubi_volume *vol)
 472{
 473        return 0;
 474}
 475
 476#define ubi_gluebi_updated(vol)
 477#endif
 478
 479/* eba.c */
 480int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
 481                      int lnum);
 482int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 483                     void *buf, int offset, int len, int check);
 484int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
 485                      const void *buf, int offset, int len, int dtype);
 486int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
 487                         int lnum, const void *buf, int len, int dtype,
 488                         int used_ebs);
 489int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
 490                              int lnum, const void *buf, int len, int dtype);
 491int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
 492                     struct ubi_vid_hdr *vid_hdr);
 493int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
 494void ubi_eba_close(const struct ubi_device *ubi);
 495
 496/* wl.c */
 497int ubi_wl_get_peb(struct ubi_device *ubi, int dtype);
 498int ubi_wl_put_peb(struct ubi_device *ubi, int pnum, int torture);
 499int ubi_wl_flush(struct ubi_device *ubi);
 500int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
 501int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
 502void ubi_wl_close(struct ubi_device *ubi);
 503int ubi_thread(void *u);
 504
 505/* io.c */
 506int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
 507                int len);
 508int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
 509                 int len);
 510int ubi_io_sync_erase(struct ubi_device *ubi, int pnum, int torture);
 511int ubi_io_is_bad(const struct ubi_device *ubi, int pnum);
 512int ubi_io_mark_bad(const struct ubi_device *ubi, int pnum);
 513int ubi_io_read_ec_hdr(struct ubi_device *ubi, int pnum,
 514                       struct ubi_ec_hdr *ec_hdr, int verbose);
 515int ubi_io_write_ec_hdr(struct ubi_device *ubi, int pnum,
 516                        struct ubi_ec_hdr *ec_hdr);
 517int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,
 518                        struct ubi_vid_hdr *vid_hdr, int verbose);
 519int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
 520                         struct ubi_vid_hdr *vid_hdr);
 521
 522/* build.c */
 523int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset);
 524int ubi_detach_mtd_dev(int ubi_num, int anyway);
 525struct ubi_device *ubi_get_device(int ubi_num);
 526void ubi_put_device(struct ubi_device *ubi);
 527struct ubi_device *ubi_get_by_major(int major);
 528int ubi_major2num(int major);
 529
 530/*
 531 * ubi_rb_for_each_entry - walk an RB-tree.
 532 * @rb: a pointer to type 'struct rb_node' to to use as a loop counter
 533 * @pos: a pointer to RB-tree entry type to use as a loop counter
 534 * @root: RB-tree's root
 535 * @member: the name of the 'struct rb_node' within the RB-tree entry
 536 */
 537#define ubi_rb_for_each_entry(rb, pos, root, member)                         \
 538        for (rb = rb_first(root),                                            \
 539             pos = (rb ? container_of(rb, typeof(*pos), member) : NULL);     \
 540             rb;                                                             \
 541             rb = rb_next(rb), pos = container_of(rb, typeof(*pos), member))
 542
 543/**
 544 * ubi_zalloc_vid_hdr - allocate a volume identifier header object.
 545 * @ubi: UBI device description object
 546 * @gfp_flags: GFP flags to allocate with
 547 *
 548 * This function returns a pointer to the newly allocated and zero-filled
 549 * volume identifier header object in case of success and %NULL in case of
 550 * failure.
 551 */
 552static inline struct ubi_vid_hdr *
 553ubi_zalloc_vid_hdr(const struct ubi_device *ubi, gfp_t gfp_flags)
 554{
 555        void *vid_hdr;
 556
 557        vid_hdr = kzalloc(ubi->vid_hdr_alsize, gfp_flags);
 558        if (!vid_hdr)
 559                return NULL;
 560
 561        /*
 562         * VID headers may be stored at un-aligned flash offsets, so we shift
 563         * the pointer.
 564         */
 565        return vid_hdr + ubi->vid_hdr_shift;
 566}
 567
 568/**
 569 * ubi_free_vid_hdr - free a volume identifier header object.
 570 * @ubi: UBI device description object
 571 * @vid_hdr: the object to free
 572 */
 573static inline void ubi_free_vid_hdr(const struct ubi_device *ubi,
 574                                    struct ubi_vid_hdr *vid_hdr)
 575{
 576        void *p = vid_hdr;
 577
 578        if (!p)
 579                return;
 580
 581        kfree(p - ubi->vid_hdr_shift);
 582}
 583
 584/*
 585 * This function is equivalent to 'ubi_io_read()', but @offset is relative to
 586 * the beginning of the logical eraseblock, not to the beginning of the
 587 * physical eraseblock.
 588 */
 589static inline int ubi_io_read_data(const struct ubi_device *ubi, void *buf,
 590                                   int pnum, int offset, int len)
 591{
 592        ubi_assert(offset >= 0);
 593        return ubi_io_read(ubi, buf, pnum, offset + ubi->leb_start, len);
 594}
 595
 596/*
 597 * This function is equivalent to 'ubi_io_write()', but @offset is relative to
 598 * the beginning of the logical eraseblock, not to the beginning of the
 599 * physical eraseblock.
 600 */
 601static inline int ubi_io_write_data(struct ubi_device *ubi, const void *buf,
 602                                    int pnum, int offset, int len)
 603{
 604        ubi_assert(offset >= 0);
 605        return ubi_io_write(ubi, buf, pnum, offset + ubi->leb_start, len);
 606}
 607
 608/**
 609 * ubi_ro_mode - switch to read-only mode.
 610 * @ubi: UBI device description object
 611 */
 612static inline void ubi_ro_mode(struct ubi_device *ubi)
 613{
 614        if (!ubi->ro_mode) {
 615                ubi->ro_mode = 1;
 616                ubi_warn("switch to read-only mode");
 617        }
 618}
 619
 620/**
 621 * vol_id2idx - get table index by volume ID.
 622 * @ubi: UBI device description object
 623 * @vol_id: volume ID
 624 */
 625static inline int vol_id2idx(const struct ubi_device *ubi, int vol_id)
 626{
 627        if (vol_id >= UBI_INTERNAL_VOL_START)
 628                return vol_id - UBI_INTERNAL_VOL_START + ubi->vtbl_slots;
 629        else
 630                return vol_id;
 631}
 632
 633/**
 634 * idx2vol_id - get volume ID by table index.
 635 * @ubi: UBI device description object
 636 * @idx: table index
 637 */
 638static inline int idx2vol_id(const struct ubi_device *ubi, int idx)
 639{
 640        if (idx >= ubi->vtbl_slots)
 641                return idx - ubi->vtbl_slots + UBI_INTERNAL_VOL_START;
 642        else
 643                return idx;
 644}
 645
 646#endif /* !__UBI_UBI_H__ */
 647